Jones was hospitalized in Nashville Thursday for a fever and irregular blood pressure, though the cause of death was not immediately released.

Jones was in the middle of a tour -- it was supposed to be his last -- when he fell ill. Several dates had already been canceled.

Jones' towering influence on country music was equaled only by his public persona ... which often imitated the melodrama in his songs... and was well-chronicled in the tabloids. He was married four times -- once to Tammy Wynette -- and made countless headlines for drinking, stormy romances and violent rages.

But his star-power in country music cannot be overstated. Jones has charted more country hits than any other artist ... "He Stopped Loving Her Today" is perhaps his biggest, but the list of charted hits is around 150.

He was inducted into the Country Music Hall of Fame in 1992 ... though given how much influence he had on country music ... they might as well have honored him every year.